medical_animation on Instagram: "This incredible venogram (an X-ray of the veins using contrast dye) provides a clear look at a fascinating anatomical phenomenon. As the arms are raised, watch how the subclavian vein gets compressed in the narrow space between the collarbone (clavicle) and the first rib. This “pinching” effect can temporarily block or severely reduce blood flow from the arm back to the heart. This is the underlying mechanism for a condition known as Venous Thoracic Outlet Syndro